Electronic device

ABSTRACT

An electronic device includes a chip component and a metal terminal. The chip component includes a terminal electrode formed on an element body. The metal terminal is connectable with the terminal electrode of the chip component. The metal terminal includes a terminal body and a pair of holding pieces. The terminal body faces an end surface of the terminal electrode of the chip component. The pair of holding pieces is formed on the terminal body and sandwiches the chip component. A width, a protrusion length, or a protrusion area of one of the pair of holding pieces is different from that of the other holding piece.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to an electronic device with a metal terminal.

2. Description of the Related Art

In addition to a normal chip component that is solely directly mounted on a board, as shown in Patent Document 1 for example, a chip component attached with a metal terminal is proposed as an electronic device, such as a ceramic capacitor.

It is reported that the electronic device attached with a metal terminal after being mounted has a reduction effect on a deformation stress that travels from a board to a chip component and a protection effect on a chip component from impacts or so. Thus, the electronic device attached with a metal terminal is used in a field where durability, reliability, and the like are required.

In conventional electronic devices with a metal terminal, however, a terminal electrode of a chip component and a metal terminal are joined by only a solder, and there is a problem with the joint. For example, the soldering operation needs to be conducted while the terminal electrode of the chip component and the metal terminal are being positioned. In particular, when a plurality of chip components is soldered to a pair of metal terminals, this operation is complicated, and the joint reliability may decrease. When used in a high temperature environment, an environment with a large temperature change, or the like, a joint between the chip component and the metal terminal may be released due to a difference in thermal expansion coefficient between a solder and the metal terminal.

-   Patent Document 1: JP 2000-235932 A

SUMMARY OF THE INVENTION

The present invention has been achieved under such circumstances. It is an object of the invention to provide an electronic device with a metal terminal capable of securely and firmly connecting between a chip component and the metal terminal.

To achieve the above object, an electronic device according to a first aspect of the present invention includes:

a chip component including a terminal electrode formed on an element body; and

a metal terminal connectable with the terminal electrode of the chip component, wherein

the metal terminal includes:

-   -   a terminal body facing an end surface of the terminal electrode         of the chip component; and     -   a pair of holding pieces formed on the terminal body and         sandwiching the chip component, and

a width of one of the pair of holding pieces is different from that of the other holding piece.

An electronic device according to a second aspect of the present invention includes:

a chip component including a terminal electrode formed on an element body; and

a metal terminal connectable with the terminal electrode of the chip component, wherein

the metal terminal includes:

-   -   a terminal body facing an end surface of the terminal electrode         of the chip component; and     -   a pair of holding pieces formed on the terminal body and         sandwiching the chip component, and

a protrusion length of one of the pair of holding pieces is different from that of the other holding piece.

An electronic device according to a third aspect of the present invention includes:

a chip component including a terminal electrode formed on an element body; and

a metal terminal connectable with the terminal electrode of the chip component, wherein

the metal terminal includes:

-   -   a terminal body facing an end surface of the terminal electrode         of the chip component; and     -   a pair of holding pieces formed on the terminal body and         sandwiching the chip component, and

a protrusion area of one of the pair of holding pieces is different from that of the other holding piece.

In the metal terminal of the electronic device of the present invention, a width, a protrusion length, or a protrusion area of one of the holding pieces among the pair of holding pieces is different from the corresponding width, protrusion length, or protrusion area of the other holding piece. Thus, a holding force of one of the holding pieces can easily be adjusted and balanced with a holding force of the other holding piece. As a result, the pair of holding pieces can stably hold the chip component, and the chip component and the metal terminal can securely and firmly be connected.

For example, a holding force of the holding piece for the chip component is varied by changing a width, a protrusion length, or a protrusion area of the holding piece. Then, a holding force of one of the holding pieces for the chip component can be balanced and optimized with a holding force of the other holding piece for the chip component by adjusting a width, a protrusion length, or a protrusion area of the holding piece.

For example, a holding force of one of the holding pieces for the chip component can be weakened and optimized by reducing a width of one of the holding pieces, but may be optimized by increasing a width of one of the holding pieces. A holding force of one of the holding pieces for the chip component can be weakened and optimized by increasing a protrusion length of one of the holding pieces, but may be optimized by reducing a width of one of the holding pieces. Likewise, holding forces of the pair of holding pieces for the chip component can also be optimized by balancing a protrusion area of one of the holding pieces and a protrusion area of the other holding piece.

For example, a width of one of the holding piece may be 0.2 to 0.95 times smaller than a width of the other holding piece, a length of one of the holding pieces may be 0.5 to 0.95 times smaller than a length of the other holding piece, and a protrusion area of one of the holding pieces may be 0.5 to 1.5 times smaller than a protrusion area of the other holding piece.

A width of one of the pair of holding pieces may vary from a base toward a tip of the holding piece. In this structure, the pair of holding pieces holds the chip component more securely. In addition, a contact area between the pair of holding pieces and the terminal electrode of the chip component can be increased, and the chip component can be held more securely.

The other holding piece may be made of a plate piece corresponding to a punched hole formed in the middle of the terminal body. A holding force of one of the holding pieces can be balanced with a holding force of the other holding piece made of a plate piece corresponding to a punched hole, and the pair of holding pieces can stably hold the chip component.

Preferably, the metal terminal further includes a mount portion configured to be mounted on a mount surface, the pair of holding pieces is formed on the terminal body so as to be positioned on both sides in a longitudinal direction of the end surface of the terminal electrode of the chip component, and one of the holding pieces is positioned farther from the mount portion than the other holding piece.

In this arrangement, the metal terminal easily holds a plurality of chip components horizontally arranged side by side.

For example, the terminal body is connectable to ends of a plurality of chip components horizontally arranged side by side, the pair of holding pieces is formed on the main body for each of the chip components, and one of the pair of holding pieces in each of the chip components is formed at one end of the terminal body.

Preferably, a space region between the terminal body and the end surface of the terminal electrode includes:

a joint region having a connection member connecting the terminal body and the end surface of the terminal electrode within a predetermined range; and

a non-joint region failing to have the connection member between an edge of the joint region and the holding piece.

In the electronic device according to the present invention, the holding pieces of the metal terminal hold the chip component, and the connection member, such as a solder, connects the metal terminal and the chip component in the joint region within a predetermined range, whereby the metal terminal and the chip component can be joined securely and firmly. Incidentally, the connection member is not limited to a solder, and may be a conductive adhesive or so.

A non-joint gap between the terminal body and the end surface of the terminal electrode may become larger toward the holding piece in the non-joint region. In this structure, the terminal body of the metal terminal is freely elastically deformable in the non-joint region without being disturbed by the terminal electrode, and stress is reduced. This favorably maintains an elastic property of the holding piece continuing to the non-joint region, and the chip component can favorably be held by the holding pieces. In addition, the metal terminal is easily elastically deformed, and an acoustic noise phenomenon can be prevented effectively.

Preferably, the end surfaces of the terminal electrodes of the plurality of chip components are joined with the terminal body while being arranged adjacent to each other in a plurality of joint regions, and the non-joint region is also formed between the adjacent joint regions. In this structure, each of the chip components is easily connected by a pair of metal terminals, and an acoustic noise phenomenon can favorably be prevented due to existence of the non-joint region existing between the chip components.

Preferably, a through hole going through front and back surfaces of the terminal body may be formed in the joint region. An application state of the connection member in the joint region can be observed from outside via the through hole. Moreover, bubbles contained in the connection member, such as solder, can be released via the through hole. This stabilizes the joint even if the amount of the connection member, such as solder, is small.

Protrusions protruding toward the end surface of the terminal electrode may be formed on an inner surface of the terminal body in the joint region. This structure can easily control an application area of the connection member and also easily control a thickness of the joint region. In addition, this structure stabilizes the connection of the connection member even if the amount of the connection member is small.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic perspective view illustrating a ceramic electronic device according to an embodiment of the present invention.

FIG. 1B is a schematic perspective view of a metal terminal shown in FIG. 1A.

FIG. 1C is a plane view of the metal terminal shown in FIG. 1B.

FIG. 1D is a schematic perspective view illustrating a ceramic electronic device according to another embodiment of the present invention.

FIG. 2A is a front view of the ceramic electronic device shown in FIG. 1A.

FIG. 2B is an enlarged view of a main part of the ceramic electronic device shown in FIG. 2A.

FIG. 3A is a left-side view of the ceramic electronic device shown in FIG. 1.

FIG. 3B is a left-side view of a ceramic electronic device according to a variation of the embodiment shown in FIG. 3A.

FIG. 3C is a left-side view of a ceramic electronic device according to another embodiment of the present invention.

FIG. 3D is a left-side view of a ceramic electronic device according to further another embodiment of the present invention.

FIG. 3E is a left-side view of a ceramic electronic device according to further another embodiment of the present invention.

FIG. 4 is a top view of the ceramic electronic device shown in FIG. 1A.

FIG. 5 is a bottom view of the ceramic electronic device shown in FIG. 1A.

FIG. 6 is a cross-sectional view perpendicular to the Y-axis of the ceramic electronic device shown in FIG. 1A.

FIG. 7 is a schematic perspective view illustrating a ceramic electronic device according to another embodiment of the present invention.

FIG. 8 is a front view of the ceramic electronic device shown in FIG. 7.

FIG. 9 is a left-side view of the ceramic electronic device shown in FIG. 7.

FIG. 10 is a top view of the ceramic electronic device shown in FIG. 7.

FIG. 11 is a bottom view of the ceramic electronic device shown in FIG. 7.

FIG. 12 is a schematic perspective view illustrating a ceramic electronic device according to a variation of the embodiment shown in FIG. 7.

FIG. 13 is a schematic perspective view illustrating a ceramic electronic device according to a variation of the embodiment shown in FIG. 12.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, the present invention is described based on embodiments shown in the figures.

First Embodiment

FIG. 1A is a schematic perspective view illustrating a capacitor 10 as an electronic device according to First Embodiment of the present invention. The capacitor 10 has capacitor chips 20 as chip components and a pair of metal terminals 30 and 40. The capacitor 10 according to First Embodiment has the two capacitor chips 20, but the capacitor 10 may have a single capacitor chip 20 or any plural capacitor chips 20.

Incidentally, each embodiment is described with a capacitor where the capacitor chips 20 are equipped with the metal terminals 30 and 40, but the ceramic electronic device of the present invention is not limited to this capacitor, and may be a chip component other than capacitors equipped with the metal terminals 30 and 40.

In the figures, the X-axis, the Y-axis, and the Z-axis are perpendicular to each other, the X-axis is parallel to a direction where the capacitor chips 20 are arranged as shown in FIG. 1A, the Z-axis corresponds with a height direction of the capacitor 10 from a mount surface, and the Y-axis corresponds with a direction where a pair of terminal electrodes 22 and 24 of the chip 20 is mutually arranged on the opposite side.

The capacitor chips 20 have an approximately rectangular parallelepiped shape, and each of the two capacitor chips 20 has approximately the same shape and size. As shown in FIG. 2A, the capacitor chips 20 have a pair of chip end surfaces facing each other, and the pair of chip end surfaces consists of a first end surface 20 a and a second end surface 20 b. As shown in FIG. 1A, FIG. 2A, and FIG. 4, the first and second end surfaces 20 a and 20 b have an approximately rectangular shape. In four sides constituting each rectangle of the first and second end surfaces 20 a and 20 b, a pair of longer sides is chip first sides 20 g (see FIG. 2A), and a pair of shorter sides is chip second sides 20 h (see FIG. 4).

The capacitor chips 20 are arranged so that the first end surfaces 20 a and the second end surfaces 20 b are perpendicular to a mount surface. In other words, the chip third sides 20 j (see FIG. 2A) of the capacitor chips 20 connecting between the first end surfaces 20 a and the second end surfaces 20 b are parallel to the mount surface of the capacitor 10. Incidentally, the mount surface of the capacitor 10 is a surface attached with the capacitor 10 by solder or so and facing mount portions 38 and 48 of the metal terminals 30 and 40 mentioned below, and is a parallel surface to the X-Y plane shown in FIG. 1A.

Compared a length L1 of the chip first side 20 g shown in FIG. 2A with a length L2 of the chip second side 20 h shown in FIG. 4, the chip second side 20 h is shorter than the chip first side 20 g (L1>L2). The chip first side 20 g and the chip second side 20 h have any length ratio, but L2/L1 is about 0.3 to 0.7, for example.

The capacitor chips 20 are arranged so that the chip first sides 20 g are perpendicular to the mount surface as shown in FIG. 2A, and that the chip second sides 20 h are parallel to the mount surface as shown in FIG. 4. In the first to fourth side surfaces 20 c to 20 f (the four chip side surfaces connecting the first end surfaces 20 a and the second end surfaces 20 b), the first and second side surfaces 20 c and 20 d have large areas and are arranged perpendicularly to the mount surface, and the third and fourth side surfaces 20 e and 20 f have areas that are smaller than those of the first and second side surfaces 20 c and 20 d and are arranged in parallel to the mount surface. The third side surfaces 20 e are upper side surfaces facing the opposite direction to the mount portions 38 and 48 below, and the fourth sides surfaces 20 f are lower side surfaces facing the mount portions 38 and 48.

As shown in FIG. 1A, FIG. 2A, and FIG. 4, first terminal electrodes 22 of the capacitor chips 20 are formed to range from the first end surfaces 20 a to a part of the first to fourth side surfaces 20 c to 20 f Thus, the first terminal electrode 22 has a part arranged on the first end surface 20 a and a part arranged on the first to fourth side surfaces 20 c and 20 f.

The second terminal electrodes 24 of the capacitor chips 20 are formed to range from the second end surfaces 20 b to another part of the first to fourth side surfaces 20 c to 20 f (a different part from the part where the first terminal electrodes 22 reach). Thus, the second terminal electrode 24 has a part arranged on the second end surface 20 b and a part arranged on the first to fourth side surfaces 20 c to 20 f (see FIG. 1, FIG. 2A, and FIG. 4). The first terminal electrodes 22 and the second terminal electrodes 24 are arranged with a predetermined distance on the first to fourth side surfaces 20 c to 20 f.

As shown in FIG. 6, which schematically illustrates an internal structure of the capacitor chips 20, the capacitor chips 20 are a multilayer capacitor where internal electrode layers 26 and dielectric layers 28 are laminated. In the internal electrode layers 26, internal electrode layers 26 connected with the first terminal electrodes 22 and internal electrode layers 26 connected with the second terminal electrodes 24 are laminated alternately by sandwiching the dielectric layers 28.

As shown in FIG. 6, the internal electrode layers 26 of the capacitor chips 20 have a lamination direction that is parallel to the X-axis and perpendicular to the Y-axis. That is, the internal electrode layers 26 shown in FIG. 6 are arranged in parallel to the plane of the Z-axis and the Y-axis and perpendicularly to the mount surface.

The dielectric layers 28 of the capacitor chips 20 are composed of any dielectric material, such as calcium titanate, strontium titanate, barium titanate, and a mixture thereof. Each of the dielectric layers 28 has any thickness, but normally has a thickness of 1 μm to several hundred μm. In the present embodiment, each of the dielectric layers 28 preferably has a thickness of 1.0 to 5.0 μm. The dielectric layers 28 preferably have a main component of barium titanate, which can increase capacitance of capacitors.

The internal electrode layers 26 contain any conductive material, but may contain a comparatively inexpensive base metal when the dielectric layers 28 are composed of a reduction resistant material. The base metal is preferably Ni or a Ni alloy. The Ni alloy is preferably an alloy of Ni and one or more elements of Mn, Cr, Co, and Al, and preferably contains Ni at 95 wt % or more. Incidentally, Ni or the Ni alloy may contain various fine components, such as P, at about 0.1 wt % or less. The internal electrode layers 26 may be formed using a commercially available electrode paste. Each of the internal electrode layers 26 has a thickness appropriately determined based on usage or so.

The first and second terminal electrodes 22 and 24 are also composed of any material. The first and second terminal electrodes 22 and 24 are normally composed of copper, copper alloy, nickel, nickel alloy, or the like, but may be composed of silver, an alloy of silver and palladium, or the like. Each of the first and second terminal electrodes 22 and 24 also has any thickness, but normally has a thickness of about 10 to 50 μm. Incidentally, at least one metal film of Ni, Cu, Sn, etc. may be formed on the surfaces of the first and second terminal electrodes 22 and 24.

The capacitor chips 20 have shape and size that are appropriately determined based on object and usage. For example, the capacitor chip 20 has a length (L3 shown in FIG. 2A) of 1.0 to 6.5 mm, preferably 3.2 to 5.9 mm, a width (L1 shown in FIG. 2A) of 0.5 to 5.5 mm, preferably 1.6 to 5.2 mm, and a thickness (L2 shown in FIG. 4) of 0.3 to 3.5 mm, preferably 0.8 to 3.2 mm. When the capacitor 10 has a plurality of capacitor chips 20, each of the capacitor chips 20 may have mutually different size and shape.

A pair of metal terminals 30 and 40 of the capacitor 10 is arranged correspondingly with the first and second end surfaces 20 a and 20 b (a pair of chip end surfaces). That is, the first metal terminal 30 (one of the pair of metal terminals 30 and 40) is arranged correspondingly with the first terminal electrodes 22 (one of the pair of terminal electrodes 22 and 24), and the second metal terminal 40 (the other of the pair of metal terminals 30 and 40) is arranged correspondingly with the second terminal electrodes 24 (the other of the pair of terminal electrodes 22 and 24).

The first metal terminal 30 has a terminal body 36, a plurality of pairs of engagement arm portions (holding pieces) 31 a, 31 b, 33 a, and 33 b, and a mount portion 38. The terminal body 36 faces the first terminal electrodes 22. The engagement arm portions 31 a, 31 b, 33 a, and 33 b sandwich and hold the capacitor chips 20 from both ends of the chip first sides 20 g in the Z-axis direction. The mount portion 38 extends from the terminal body 36 toward the capacitor chips 20 and is at least partially approximately perpendicular to the terminal body 36.

As shown in FIG. 2A, the terminal body 36 has a substantially rectangular flat shape having a pair of terminal first sides 36 g approximately parallel to the chip first sides 20 g perpendicular to the mount surface and a pair of terminal second sides 36 ha and 36 hb approximately parallel to the chip second sides 20 h parallel to the mount surface as shown in FIG. 3A.

As shown in FIG. 3A and FIG. 3B (First Variation), the terminal second sides 36 ha and 36 hb parallel to the mount surface have a length that is several times plus or minus alpha of a length L2 (see FIG. 4) of the chip second sides 20 h arranged in parallel to the terminal second sides 36 ha and 36 hb. That is, the terminal body 36 has a width in the X-axis that may be equal to, slightly shorter, or slightly longer than a length obtained by multiplying the number of capacitor chips 20 contained in the capacitor 10 shown in FIG. 3A or a capacitor 200 shown in FIG. 3B with a width of the capacitor chips 20 in the X-axis direction.

For example, the capacitor 200 according to First Variation shown in FIG. 3B includes two capacitor chips 20, and terminal second sides 36 ha and 36 hb parallel to a mount surface have a length that is shorter than a double of a length L2 of a chip second side 20 h arranged in parallel to the terminal second sides 36 ha and 36 hb. Incidentally, the capacitor 200 is the same as the capacitor 10 shown in FIG. 1A to FIG. 6 except that the chip second sides of the capacitor chips 20 are longer than the chip second sides 20 h of the capacitor chips 20 according to the embodiment.

On the other hand, the capacitor 10 according to First Embodiment shown in FIG. 3A includes two capacitor chips 20, and the terminal second sides 36 ha and 36 hb parallel to the mount surface have a length that is the same as or slightly longer than a double of a length L2 of the chip second side 20 h arranged in parallel to the terminal second sides 36 ha and 36 hb. As shown in FIG. 1A, a capacitor chip that can be combined with the metal terminals 30 and 40 does not have the only one size, and the metal terminals 30 and 40 can constitute an electronic device correspondingly with multiple kinds of capacitor chips 20 having different lengths in the X-axis direction.

The terminal body 36 is electrically and mechanically connected with the first terminal electrodes 22 formed on the first end surfaces 20 a facing the terminal body 36. For example, the terminal body 36 and the first terminal electrodes 22 can be connected with each other by arranging a conductive connection member 50, such as a solder and a conductive adhesive, in a space between the terminal body 36 and the first terminal electrodes 22 shown in FIG. 2A.

Joint regions 50 a are determined as a region where the connection member 50 joins the terminal body 36 and the end surfaces of the first terminal electrodes 22. A non-joint region 50 b is determined as a region where the terminal body 36 and the end surfaces of the first terminal electrodes 22 are not joined without the connection member 50, and a space exists between the terminal body 36 and the end surfaces of the first terminal electrodes 22. The space between the terminal body 36 and the end surfaces of the first terminal electrodes 22 in the non-joint region 50 b has a thickness that is approximately equal to a thickness of the connection member 50. In the present embodiment, the connection member 50 has a thickness that is determined based on a height of protrusions 36 a mentioned below or so. A height of the joint region 50 a in the Z-axis direction shown in FIG. 2A corresponds to a first predetermined height.

In the present embodiment, first through holes 36 b (see FIG. 1A) are formed on a part of the terminal body 36 facing the first end surfaces 20 a. Two first through holes 36 b are formed correspondingly with the capacitor chips 20 contained in the capacitor 10, but any shape and number of first through holes 36 b may be formed. In the present embodiment, the first through hole 36 b is formed in an approximately central part of the joint region 50 a.

As shown in FIG. 3A, the joint region 50 a is formed by applying the connection member 50 (see FIG. 2A) to initial application regions 50 c respectively positioned on both sides of the first through hole 36 b in the Z-axis direction. That is, after the connection member 50 is applied, the joint region 50 a is formed in such a manner that the connection member 50 applied on the initial application regions 50 c spreads out by bringing a heating element into contact with the outer surface of the terminal body 36 and pushing it against the end surface of the chip 20. The non-joint region 50 b is a region where the connection member 50 is not spread out. In the present embodiment, a total area of the non-joint region 50 b between the terminal body 36 and the end surfaces of the terminal electrodes 22 in the Y-axis direction is larger than 3/10, preferably ½ to 10, of a total area of the joint regions 50 a.

In the present embodiment, the connection member 50 composed of a solder forms a solder bridge between a periphery of the first through hole 36 b and the first terminal electrode 22, and the terminal body 36 and the first terminal electrode 22 can thereby be joined strongly. Moreover, an application state of the connection member 50 in the joint region 50 a can be observed from outside via the first through hole 36 b. Moreover, bubbles contained in the connection member 50, such as a solder, can be released via the first through hole 36 b. This stabilizes the joint even if the amount of the connection member 50, such as a solder, is small.

The terminal body 36 is provided with a plurality of protrusions 36 a protruding toward the first end surfaces 20 a of the capacitor chips 20 and touching the first end surfaces 20 a so that the plurality of protrusions 36 a surrounds the first through holes 36 b. In addition, the protrusions 36 a may be formed outside the initial application regions 50 c, or the initial application regions 50 c may be positioned between the protrusions 36 a and the first through hole 36 b. Incidentally, the initial application region 50 c may protrude from between the protrusion 36 a and the first through hole 36 b.

The protrusions 36 a reduce a contact area between the terminal body 36 and the first terminal electrodes 22. This makes it possible to prevent a vibration generated in the chip capacitors 20 from traveling to the mount board via the first metal terminal 30 and prevent an acoustic noise of the ceramic capacitor 10.

The protrusions 36 a are formed around the first through hole 36 b, and the joint region 50 a formed by the spread of the connection member 50, such as a solder, can thereby be adjusted. In the present embodiment, the joint region 50 a has a periphery positioned slightly outside the protrusions 36 a. In particular, as shown in FIG. 1A, a lower end of the joint region 50 a in the Z-axis direction is positioned near an upper opening edge of a second through hole (opening) 36 c mentioned below.

In such a capacitor 10, an acoustic noise can be prevented while a connection strength between the terminal body 36 and the first terminal electrodes 22 is adjusted in an appropriate range. Incidentally, four protrusions 36 a are formed around one first through hole 36 b in the capacitor 10, but any number and arrangement of the protrusions 36 a may be employed.

The terminal body 36 is provided with second through holes (openings) 36 c having a periphery portion connected with the lower arm portion 31 b or 33 b (one of multiple pairs of the engagement arm portions 31 a, 31 b, 33 a, and 33 b). The lower arm portion 31 b or 33 b is formed by a plate piece corresponding to a punched hole (second through hole 36 c) formed on the terminal body 36 and is formed in the middle of the terminal body 36 in the Z-axis direction. The second through holes 36 c are positioned closer to the mount portion 38 than the first through holes 36 b. Unlike the first through holes 36 b, the second through holes 36 c are not provided with any connection member, such as a solder. That is, the second through holes 36 c are formed in the non-joint region 50 b.

In the first metal terminal 30, non-opening regions 36 c 1 are located on both sides of each second through hole 36 c in the X-axis direction with the lower arm portion 31 b (33 b) supporting the capacitor chip 20. The non-opening regions 36 c 1 function as the non-joint region 50 b between the first metal terminal 30 and the terminal electrodes 22 and have an easily deformable shape. The first metal terminal 30 can thereby effectively demonstrate a reduction effect on stress generated in the capacitor 10 and an absorption effect on vibration of the capacitor chips 20. Thus, the capacitor 10 having the first metal terminal 30 can favorably prevent an acoustic noise and have a favorable connection reliability with the mount board when being mounted.

The second through holes 36 c have any shape, but preferably have an opening width in the width direction (a parallel direction (X-axis direction) to the terminal second sides 36 ha and 36 hb) that is wider than the first through holes 36 b. When the second through holes 36 c have a wide opening width, the first metal terminal 30 can effectively enhance a reduction effect on stress and a prevention effect on acoustic noise. When the first through holes 36 b have an opening width that is narrower than the second through holes 36 c, the connection member does not spread excessively. As a result, it is possible to prevent an excessive rise in connection strength between the capacitor chips 20 and the terminal body 36 and prevent an acoustic noise.

As shown in FIG. 2A, the non-joint regions 50 b (the connection member 50 does not exist between the terminal body 36 and the end surfaces of the terminal electrodes 22) are present in the non-opening regions 36 c 1 of the terminal body 36 within a height L4 (second predetermined height) of the second through holes 36 c in the Z-axis direction shown in FIG. 3A. In the present embodiment, the height L4 (second predetermined height) of the second through holes 36 c in the Z-axis direction substantially corresponds to a height of the non-joint regions 50 b in the Z-axis direction located below the joint regions 50 a in the Z-axis direction. The height L4 may, however, be smaller than a height of the non-joint regions 50 b in the Z-axis direction.

In the present embodiment, each of the second through holes 36 c formed per chip 20 has a width in the X-axis direction that is preferably smaller than a width of each chip 20 in the X-axis direction. In the present embodiment, each of the second through holes 36 c has a width in the X-axis direction that is preferably ⅙ to ⅚, more preferably ⅓ to ⅔, of a width of each chip 20 in the X-axis direction.

In the terminal body 36, the second through hole 36 c connected with the lower arm portion 31 b is formed with a predetermined distance in the height direction against the terminal second side 36 hb connected with the mount portion 38, and a slit 36 d is formed between the second through hole 36 c and the terminal second side 36 hb.

In the terminal body 36, the slit 36 d is formed between a connection position of the lower arm portion 31 b positioned near the mount portion 38 with the terminal body 36 (a lower side of a periphery portion of the second through hole 36 c) and the terminal second side 36 hb connected with the mount portion 38. The slits 36 d extend in a parallel direction to the terminal second sides 36 ha and 36 hb. The slits 36 d can prevent a solder used at the time of mounting the capacitor 10 on a mount board from creeping up on the terminal body 36 and prevent a formation of a solder bridge connected with the lower arm portions 31 b and 33 b or the first terminal electrodes 22. Thus, the capacitor 10 with the slits 36 d demonstrates a prevention effect on acoustic noise.

As shown in FIG. 1A and FIG. 2A, the engagement arm portions 31 a, 31 b, 33 a, and 33 b of the first metal terminal 30 extend from the terminal body 36 to the third or fourth side surface 20 e or 20 f (chip side surface of the capacitor chips 20). The lower arm portion 31 b (33 b) (one of the engagement arm portions 31 a, 31 b, 33 a, and 33 b) is formed by being bent from the lower edge of the second through hole 36 c in the Z-axis direction formed on the terminal body 36. The upper arm portion 31 a (33 a) (another one of the engagement arm portions 31 a, 31 b, 33 a, and 33 b) is formed by being bent from the terminal second side 36 ha at the upper part of the terminal body 36 (positive side in the Z-axis direction). That is, the upper arm portion 31 a (33 a) is formed at the upper end of the terminal body 36 in the Z-axis direction in the present embodiment.

In the present embodiment, the upper arm portion 31 a (33 a) has a width Xa in the X-axis direction (see FIG. 1B) that is different from a width Xb of the lower arm portion 31 b (33 b) in the X-axis direction, and Xa<Xb is preferably satisfied. Xa/Xb is variable within a range of, for example, 0.2 to 0.95 (preferably, 0.5 to 0.95). In this range, a holding force of the upper arm portion 31 a (33 a) is easily adjusted and can be balanced with a holding force of the lower arm portion 31 b (33 b). As a result, the pair of arm portions 31 a and 31 b (33 a and 33 b) can stably hold the capacitor chip 20, and the capacitor chip 20 and the metal terminal 30 can securely and firmly be connected.

For example, since the lower arm portion 31 b (33 b) (one of the holding pieces) is easily deformable due to the second through hole 36 c (punched hole), the hardness of the lower arm portion 31 b (33 b) is effective for acoustic noise, but is low. Thus, if the lower arm portion 31 b (33 b) and the upper arm portion 31 a (33 a) (the other holding piece failing to be formed by a punched hole) have the same width, the pair of arm portions 31 a and 31 b (33 a and 33 b) may unstably hold the capacitor chip 20. Thus, the upper arm portion 31 a (33 a) preferably has a similar hardness to a hardness of the lower arm portion 31 b (33 b) by reducing a width of the upper arm portion 31 a (33 a). Since the upper arm portion 31 a (33 a) is not formed by a punched hole, the upper arm portion 31 a (33 a) has an easily adjustable width.

For prevention of solder bridge, the slit 36 d may be formed near the lower arm portion 31 b (33 b). In this case, the lower arm portion 31 b (33 b) has a smaller hardness, and the upper arm portion 31 a (33 a) thereby more preferably has an adjusted hardness. That is, a width Xa of the upper arm portion 31 a (33 a) in the X-axis direction is reduced compared to a width Xb of the lower arm portion 31 b (33 b) in the X-axis direction, and the upper arm portion 31 a (33 a) can thereby have a similar hardness to a hardness of the lower arm portion 31 b (33 b). Accordingly, a holding force of the upper arm portion 31 a (33 a) (one of the holding pieces) for the capacitor chip 20 can be balanced with a holding force of the lower arm portion 31 b (33 b) (the other holding piece) and can be optimized.

In the present embodiment, as shown in FIG. 1C, the upper arm portion 31 a (33 a) may have a protrusion length Ya in the Y-axis direction that is different from a protrusion length Yb of the lower arm portion 31 b (33 b) in the Y-axis direction. Preferably, Ya>Yb is satisfied. For example, Ya/Yb is variable within a range of 0.5 to 0.95. In this range, as with the relation of Xa and Xb, a holding force of the upper arm portion 31 a (33 a) can easily be adjusted and can be balanced with a holding force of the lower arm portion 31 b (33 b). As a result, the pair of arm portions 31 a and 31 b (33 a and 33 b) can stably hold the capacitor chip 20, and the capacitor chip 20 and the metal terminal 30 can securely and firmly be connected.

For example, since the lower arm portion 31 b (33 b) (one of the holding pieces) is easily deformable due to the second through hole 36 c (punched hole), the hardness of the lower arm portion 31 b (33 b) is effective for acoustic noise, but is low. Thus, if the lower arm portion 31 b (33 b) and the upper arm portion 31 a (33 a) (the other holding piece failing to be formed by a punched hole) have the same protrusion length in the Y-axis direction, the pair of arm portions 31 a and 31 b (33 a and 33 b) may unstably hold the capacitor chip 20. Thus, the upper arm portion 31 a (33 a) preferably has a similar hardness to a hardness of the lower arm portion 31 b (33 b) by increasing a protrusion length of the upper arm portion 31 a (33 a) in the Y-axis direction. Since the upper arm portion 31 a (33 a) is not formed by a punched hole, the upper arm portion 31 a (33 a) has an easily adjustable protrusion length in the Y-axis direction.

For prevention of solder bridge, the slit 36 d may be formed near the lower arm portion 31 b (33 b). In this case, the lower arm portion 31 b (33 b) has a smaller hardness, and the upper arm portion 31 a (33 a) thereby more preferably has an adjusted hardness. That is, a protrusion length Ya of the upper arm portion 31 a (33 a) in the Y-axis direction is reduced compared to a protrusion length Yb of the lower arm portion 31 b (33 b) in the Y-axis direction, and the upper arm portion 31 a (33 a) can thereby have a similar hardness to a hardness of the lower arm portion 31 b (33 b). Accordingly, a holding force of the upper arm portion 31 a (33 a) (one of the holding pieces) for the capacitor chip 20 can be balanced with a holding force of the lower arm portion 31 b (33 b) (the other holding piece) and can be optimized.

Moreover, as shown in FIG. 1C, a protrusion area Aa (=Xa×Ya) seen from the upper arm portion 31 a (33 a) in the Z-axis direction may be different from a protrusion area Ab (=Xb×Yb) seen from the lower arm portion 31 b (33 b) in the Z-axis direction. For example, Aa/Ab is variable in a range of 0.5 to 1.5. In this range, as with the relation of Xa and Xb, a holding force of the upper arm portion 31 a (33 a) can easily be adjusted and can be balanced with a holding force of the lower arm portion 31 b (33 b). As a result, the pair of arm portions 31 a and 31 b (33 a and 33 b) can stably hold the capacitor chip 20, and the capacitor chip 20 and the metal terminal 30 can securely and firmly be connected.

For example, since the lower arm portion 31 b (33 b) (one of the holding pieces) is easily deformable due to the second through hole 36 c (punched hole), the hardness of the lower arm portion 31 b (33 b) is effective for acoustic noise, but is low. Thus, if the lower arm portion 31 b (33 b) and the upper arm portion 31 a (33 a) (the other holding piece failing to be formed by a punched hole) have the same protrusion length in the Y-axis direction, the pair of arm portions 31 and 31 b (33 a and 33 b) may unstably hold the capacitor chip 20. Thus, the upper arm portion 31 a (33 a) preferably has a similar hardness to a hardness of the lower arm portion 31 b (33 b) by adjusting a protrusion area of the upper arm portion 31 a (33 a). Since the upper arm portion 31 a (33 a) is not formed by a punched hole, the upper arm portion 31 a (33 a) has an easily adjustable protrusion area.

For prevention of solder bridge, the slit 36 d may be formed near the lower arm portion 31 b (33 b). In this case, the lower arm portion 31 b (33 b) has a smaller hardness, and the upper arm portion 31 a (33 a) thereby more preferably has an adjusted hardness. That is, a protrusion area of the upper arm portion 31 a (33 a) is adjusted with a protrusion area of the lower arm portion 31 b (33 b), and the upper arm portion 31 a (33 a) can thereby have a similar hardness to a hardness of the lower arm portion 31 b (33 b). Accordingly, a holding force of the upper arm portion 31 a (33 a) (one of the holding pieces) for the capacitor chip 20 can be balanced with a holding force of the lower arm portion 31 b (33 b) (the other holding piece) and can be optimized.

As shown in FIG. 1A, the terminal body 36 has a chip facing part 36 j and a terminal connection part 36 k. The chip facing part 36 j faces the first end surfaces 20 a of the capacitor chips 20 and is positioned at a height overlapping with the first end surfaces 20 a. The terminal connection part 36 k is positioned below the chip facing part 36 j and is located at a position connecting between the chip facing part 36 j and the mount portion 38.

The second through holes 36 c are formed so that their periphery portions range the chip facing part 36 j and the terminal connection part 36 k. The lower arm portions 31 b and 33 b extend from the terminal connection part 36 k. That is, bases of the lower arm portions 31 b and 33 b are connected with lower sides (opening edges close to the mount portion 38) of approximately rectangular periphery portions of the second through holes 36 c.

The lower arm portions 31 b and 33 b extend from the bases toward inside in the Y-axis direction (toward the central parts of the chips 20) while being bent, touch the fourth side surfaces 20 f of the capacitor chips 20, and support the capacitor chips 20 from below (see FIG. 2A). Incidentally, the lower arm portions 31 b and 33 b may tilt upward in the Z-axis direction from the lower sides of the periphery portions of the second through holes 36 c before the chips 20 are attached. This enables the lower arm portions 31 b and 33 b to touch the fourth side surfaces 20 f of the chips 20 due to the resilience of the lower arm portions 31 b and 33 b.

Lower edges (chip second sides 20 h below) of the first end surfaces 20 a of the capacitor chips 20 are positioned slightly above the lower sides of the periphery portions of the second through holes 36 c, which are the bases of the lower arm portions 31 b and 33 b. When the capacitor chips 20 are viewed in the Y-axis direction as shown in FIG. 3A, the lower edges (chip second sides 20 h below) of the first end surfaces 20 a of the capacitor chips 20 can be recognized from the side of the capacitor 10 via the second through holes 36 b.

As shown in FIG. 1A, a pair of upper arm portion 31 a and lower arm portion 31 b holds one capacitor chip 20, and a pair of upper arm portion 33 a and lower arm portion 33 b holds another one capacitor chip 20. Since a pair of upper arm portion 31 a and lower arm portion 31 b (or upper arm portion 33 a and lower arm portion 33 b) holds one capacitor chip 20, not multiple capacitor chips 20, the first metal terminal 30 can definitely hold each of the capacitor chips 20.

The pair of upper arm portion 31 a and lower arm portion 31 b does not hold the capacitor chip 20 from both ends of the chip second sides 20 h (shorter sides of the first end surface 20 a), but holds the capacitor chip 20 from both ends of the chip first sides 20 g (longer sides of the first end surface 20 a). This increases a distance between the upper arm portion 31 a (33 a) and the lower arm portion 31 b (33 b) and easily absorbs a vibration of the capacitor chip 20. Thus, the capacitor 10 can favorably prevent an acoustic noise. Incidentally, since the lower arm portions 31 b and 33 b extend from the terminal connection part 36 k, the capacitor chips 20 have a short transmission path between the first terminal electrodes 22 and the mount board, compared to when the lower arm portions 31 b and 33 b are connected with the chip facing part 36 j.

The mount portion 38 is connected with the terminal second side 36 hb below in the terminal body 36 (negative side in the Z-axis direction). The mount portion 38 extends from the terminal second side 36 hb below toward the capacitor chips 20 (negative side in the Y-axis direction) and is bent approximately perpendicularly to the terminal body 36. Incidentally, the top surface of the mount portion 38 (a surface of the mount portion 38 closer to the capacitor chips 20) preferably has a solder wettability that is lower than a solder wettability of the bottom surface of the mount portion 38 in order to prevent an excessive scattering of a solder used when the capacitor chips 20 are mounted on a board.

The mount portion 38 of the capacitor 10 is mounted on a mount surface, such as a mount board, in a position facing downward as shown in FIG. 1A and FIG. 2A. Thus, a height of the capacitor 10 in the Z-axis direction is a height of the capacitor 10 when being mounted. In the capacitor 10, the mount portion 38 is connected with the terminal second side 36 hb on one side of the terminal body 36, and the upper arm portions 31 a and 33 a are connected with the terminal second side 36 ha on the other side of the terminal body 36. Thus, the capacitor 10 has no unnecessary part of the length in the Z-axis direction and is advantageous for low profile.

Since the mount portion 38 is connected with the terminal second side 36 hb on one side of the terminal body 36, the capacitor 10 can have a small projected area in the Z-axis direction and have a small mount area, compared to prior arts where the mount portion 38 is connected with the terminal first sides 36 g of the terminal body 36. Since the third and fourth side surfaces 20 e and 20 f having small areas among the first to fourth side surfaces 20 c to 20 f of the capacitor chips 20 are arranged in parallel to the mount surface as shown in FIG. 1A, FIG. 5, etc., the capacitor 10 can have a small mount area even if the capacitor chips 20 are not overlapped with each other in the height direction.

As shown in FIG. 1A and FIG. 2A, the second metal terminal 40 has a terminal body 46, a plurality of pairs of engagement arm portions 41 a, 41 b, 43 a, and 43 b, and a mount portion 48. The terminal body 46 faces the second terminal electrodes 24. The engagement arm portions 41 a, 41 b, 43 a, and 43 b sandwich and hold the capacitor chips 20 from both ends of the chip first sides 20 g in the Z-axis direction. The mount portion 48 extends from the terminal body 46 toward the capacitor chips 20 and is at least partially approximately perpendicular to the terminal body 46.

As is the case with the terminal body 36 of the first metal terminal 30, the terminal body 46 of the second metal terminal 40 has a pair of terminal first sides 46 g approximately parallel to the chip first sides 20 g and a terminal second side 46 ha approximately parallel to the chip second sides 20 h. The terminal body 46 is provided with protrusions (not illustrated), first through holes (not illustrated), second through holes (not illustrated), and slits 46 d (see FIG. 6), all of which are similar to the protrusions 36 a, the first through holes 36 b, the second through holes 36 c, and the slits 36 d formed on the terminal body 36.

In the present embodiment, as shown in FIG. 2B, the terminal body 36 of the first metal terminal 30 is warped from the end surface of the terminal electrode 22 toward the arm portions 31 a and 31 b (holding pieces) in the non-joint regions 50 b. In the non-joint regions 50 b, a non-joint gap 50 d between the terminal body 36 and the end surface of the terminal electrode 22 consequently becomes larger toward the arm portions 31 a and 31 b.

A warp angle θa (upper one in the Z-axis direction) of the terminal body 36 from the end surface of the terminal electrode 22 in the non-joint region 50 b may be equal to or different from a warp angle θb (lower one in the Z-axis direction) of the terminal body 36 from the end surface of the terminal electrode 22 in the non-joint region 50 b. A maximum width of the non-joint gap 50 d is 1.2 to 7 times larger than a minimum width of the non-joint gap 50 d.

Incidentally, a minimum width of the non-joint gap 50 d is as large as a thickness of the connection member 50. In this range, the arm portions 31 a and 31 b continuing to the non-joint region 50 b can have a favorable elasticity and favorably hold the capacitor chip 20, the metal terminal 30 can easily elastically be deformed, and an acoustic noise phenomenon can effectively be prevented.

As shown in FIG. 1A, the second metal terminal 40 is arranged symmetrically to the first metal terminal 30 and is different from the first metal terminal 30 in arrangement against the capacitor chips 20. The second metal terminal 40 is, however, different from the first metal terminal 30 only in arrangement against the capacitor chips 20 and has a similar shape to the first metal terminal 30. Thus, the second metal terminal 40 is not described in detail.

The first metal terminal 30 and the second metal terminal 40 are composed of any conductive metal material, such as iron, nickel, copper, silver, and an alloy thereof. In particular, the first and second metal terminals 30 and 40 are preferably composed of copper in consideration of restraining resistivity of the first and second metal terminals 30 and 40 and reducing ESR of the capacitor 10.

Method of Manufacturing Multilayer Capacitor Chip 20

Hereinafter, a method of manufacturing the capacitor 10 is described.

In a manufacture of the multilayer capacitor chip 20, a laminated body is prepared by laminating green sheets (to be the dielectric layers 28 after firing) with electrode patterns to be the internal electrode layers 26 after firing, and a capacitor element body is obtained by pressurizing and firing the obtained laminated body. Moreover, the first and second terminal electrodes 22 and 24 are formed on the capacitor element body by baking and plating a terminal electrode paint, and the capacitor chip 20 is thereby obtained.

A paint for green sheets and a paint for internal electrode layers (raw materials of the laminated body), a raw material of the terminal electrodes, firing conditions of the laminated body and the electrodes, and the like are not limited and can be determined with reference to known methods or so. In the present embodiment, ceramic green sheets whose main component is barium titanate are used as a dielectric material. In the terminal electrodes, a Cu paste is immersed and baked to form a baked layer, and a Ni plating treatment and a Sn plating treatment are conducted, whereby Cu baked layer/Ni plating layer/Sn plating layer is formed.

Method of Manufacturing Metal Terminals 30 and 40

In a manufacture of the first metal terminal 30, a metal plate is initially prepared. The metal plate is composed of any conductive metal material, such as iron, nickel, copper, silver, and an alloy thereof. Next, the metal plate is machined into intermediate members having shapes of the engagement arm portions 31 a to 33 b, the terminal body 36, the mount portion 38, and the like.

Next, a metal film is formed by plating on the surfaces of the intermediate members formed by machining, and the first metal terminal 30 is obtained. Any material, such as Ni, Sn, and Cu, is used for the plating. In the plating treatment, a resist treatment against a top surface of the mount portion 38 can prevent the plating from attaching to the top surface of the mount portion 38. This makes it possible to generate a difference in solder wettability between the top surface and the bottom surface of the mount portion 38. Incidentally, a similar difference can be generated by conducting a plating treatment against the entire intermediate members for formation of a metal film and removing only the metal film formed on the top surface of the mount portion 38 using a laser exfoliation or so.

In the manufacture of the first metal terminals 30, a plurality of first metal terminals 30 may be formed in a state of being connected with each other from a metal plate continuing in belt shape. The plurality of first metal terminals 30 connected with each other is cut into pieces before or after being connected with the capacitor chip 20. Incidentally, the warp of the metal terminal 30 in the non-joint region 50 b shown in FIG. 2B may be formed at the same time when or after a plurality of first metal terminals 30 is formed in a mutually connected state from a metal plate member continuing in a belt state. The second metal terminal 40 is manufactured in a similar manner to the first metal terminal 30.

Assembly of Capacitor 10

Two capacitor chips 20 obtained in the above-mentioned manner are prepared and held so that the second side surface 20 d and the first side surface 20 c are arranged to touch each other as shown in FIG. 1A. Then, a rear surface of the first metal terminal 30 faces the end surfaces of the first terminal electrodes 22 in the Y-axis direction, and the second metal terminal 40 faces the end surfaces of the second terminal electrodes 24 in the Y-axis direction.

At this time, the connection member 50 (see FIG. 2A), such as a solder, is applied to the initial application regions 50 c shown in FIG. 1A and FIG. 3A on the end surfaces of the first terminal electrodes 22 in the Y-axis direction or on the rear surface of the first metal terminal 30. The connection member 50 (see FIG. 2A), such as a solder, is similarly applied at positions corresponding with the initial application regions 50 c shown in FIG. 1A and FIG. 3A on the end surfaces of the second terminal electrodes 24 in the Y-axis direction or on the rear surface of the second metal terminal 40.

Thereafter, the joint region 50 a is formed in such a manner that the connection member 50 applied on the initial application region 50 c spreads out by pushing a heating element (not illustrated) from the outer surface of the terminal body 36 (the same applies to the terminal body 46) against the end surfaces of the chips 20. The non-joint region 50 b is a region where the connection member 50 is not spread out. This allows the first and second metal terminals 30 and 40 to be electrically and mechanically connected with the first and second terminal electrodes 22 and 24 of the capacitor chips 20. Then, the capacitor 10 is obtained.

In the capacitor 10 obtained as described above, a height direction (Z-axis direction) of the capacitor 10 is identical to directions of the chip first sides 20 g (longer sides of the capacitor chips 20), and the mount portions 38 and 48 are formed by being bent from the terminal second side 36 hb toward below the capacitor chips 20. Thus, the capacitor 10 has a small projected area in the height direction (Z-axis direction) of the capacitor 10 (see FIG. 4 and FIG. 5) and can have a small mount area.

In the capacitor 10, a plurality of capacitor chips 20 is arranged side by side in the parallel direction to the mount surface. In the capacitor 10, for example, only one capacitor chip 20 is held in the engagement direction (Z-axis direction) between a pair of engagement arm portions 31 a and 31 b. Thus, the capacitor 10 has a high connection reliability between the capacitor chip 20 and the metal terminals 30 and 40 and has a high reliability for impact and vibration.

Moreover, since a plurality of capacitor chips 20 is arranged and laminated in the parallel direction to the mount surface, the capacitor 10 has a short transmission path and can achieve a low ESL. Since the capacitor chips 20 are held perpendicularly to the lamination direction of the capacitor chips 20, the first and second metal terminals 30 and 40 can hold the capacitor chips 20 without any problems even if the length L2 of the chip second side 20 h of the capacitor chips 20 varies due to change in the lamination number of capacitor chips 20 to be held. Since the first and second metal terminals 30 and 40 can hold the capacitor chips 20 having various lamination numbers, the capacitor 10 can flexibly respond to design change.

In the capacitor 10, the upper arm portions 31 a and 33 a and the lower arm portions 31 b and 33 b sandwich and hold the capacitor chips 20 from both ends of the chip first sides 20 g (longer sides of the first end surfaces 20 a of the capacitor chips 20). Thus, the first and second metal terminals 30 and 40 can effectively demonstrate a restraint effect on stress, prevent a transmission of vibration from the capacitor chips 20 to the mount board, and prevent an acoustic noise.

In particular, since the lower arm portion 31 b (33 b) is formed by being bent from a lower opening edge of the second through hole 36 c, the lower arm portion 31 b (33 b) supporting the capacitor chip 20 and the terminal body 36 (46) supporting the lower arm portion 31 b (33 b) are elastically easily deformable. Thus, the first and second metal terminals 30 and 40 can effectively demonstrate a reduction effect on stress generated in the capacitor 10 and an absorption effect on vibrations.

Moreover, in the present embodiment, one of width Xa, protrusion length Ya, and area Aa of the upper arm portion 31 a among the pair of arm portions 31 a and 31 b (the same applies to 33 a and 33 b/the same applies hereinafter) is different from the corresponding one of width Xb, protrusion length Yb, and area Ab of the other lower arm portion 31 b. Thus, the upper arm portion 31 a can also be balanced with the lower arm portion 31 b and easily elastically be deformed. As a result, the pair of arm portions 31 a and 31 b (33 a and 33 b) can stably hold the capacitor chip 20, and the capacitor chip 20 and the metal terminal 30 can securely and firmly be connected.

For example, when the upper arm portion 31 a has a width Xa that is smaller than a width Xb (protrusion length Ya=protrusion length Yb), a holding force of the upper arm portion 31 a for the capacitor chip 20 can be weakened and balanced with a holding force of the lower arm portion 31 b for the capacitor chip 20. Alternatively, when the upper arm portion 31 a has a protrusion length Ya that is larger than a protrusion length Yb (width Xa=width Xb), a holding force of the upper arm portion 31 a for the capacitor chip 20 can be weakened and balanced with a holding force of the lower arm portion 31 b for the capacitor chip 20. Likewise, when the upper arm portion 31 a has a protrusion area Aa that is varied from a protrusion area Ab of the lower arm portion 31 b, a holding force of the upper arm portion 31 a for the capacitor chip 20 can also be weakened and balanced with a holding force of the lower arm portion 31 b for the capacitor chip 20.

Since the lower arm portions 31 b and 33 b are formed by being bent at the lower opening peripheries of the second through holes 36 c, the lower arm portions 31 b and 33 b of the capacitor 10 can be arranged at overlapping positions with the mount portion 38 in the perpendicular direction (Z-axis direction) to the mount surface (see FIG. 2A and FIG. 5). Thus, the capacitor 10 can have a wide mount portion 38 and is advantageous for downsizing.

Since the first through holes 36 b are formed, a connection state between the first and second metal terminals 30 and 40 and the chip capacitors 20 can easily be recognized from outside, and the ceramic capacitor 10 can thereby have a reduced quality dispersion and an improved non-defective product ratio.

In the capacitor 10 according to the present embodiment, a pair of engagement arm portions (holding pieces with elasticity) 31 a, 31 b, 33 a, and 33 b (the same applies to 41 a, 41 b, 43 a, and 43 b) of the metal terminal 30 (the same applies to the metal terminal 40) particularly sandwich and hold the chips 20 from both sides in the Z-axis direction. In addition, the connection member 50 (see FIG. 2), such as a solder, connects between the metal terminals 30 and 40 and the chips 20 within a predetermined range of the joint regions 50 a, and the chips 20 and the metal terminals 30 and 40 can thereby be joined definitely and firmly.

The non-joint region 50 b, which does not connect between the terminal body 36 (46) and the end surfaces of the terminal electrodes 22 (24), is formed between the peripheries of the joint regions 50 a and the engagement arm portions 31 a, 31 b, 33 a, and 33 b (the same applies to 41 a, 41 b, 43 a, and 43 b). In the non-joint region 50 b, the terminal body 36 (46) of the metal terminal 30 (40) can freely elastically be deformed without being disturbed by the terminal electrodes 22 (24), and stress is reduced. This favorably maintains an elastic property of the engagement arm portions 31 a, 31 b, 33 a, and 33 b (41 a, 41 b, 43 a, and 43 b) continuing to the non-joint region 50 b, and the chips 20 can favorably be held between a pair of engagement arm portions 31 a and 31 b and between a pair of engagement arm portions 33 a and 33 b. In addition, the metal terminal 30 (40) is easily elastically deformed, and an acoustic noise phenomenon can be prevented effectively.

A total area of the non-joint region 50 b is larger than 3/10 of a total area of the joint regions 50 a and is within a predetermined range between the terminal body 36 (46) and the end surfaces of the terminal electrodes 22 (24). This structure improves the effects of the present embodiment.

In the non-joint region 50 b, a non-joint gap 50 d being as thick as the connection member 50 is present between the terminal body 36 (46) and the end surface of the terminal electrode 22 (24). In the non-joint region 50 b, the non-joint gap 50 d between the terminal body 36 (46) and the end surface of the terminal electrode 22 (24) becomes larger toward the arm portions 31 a, 31 b, 33 a, and 33 b (41 a, 41 b, 43 a, and 43 b).

In the non-joint region 50 b, the terminal body 36 (46) of the metal terminal 30 (40) can thereby freely elastically be deformed without being disturbed by the terminal electrode 22 (24), and stress is reduced. This favorably maintains an elastic property of the engagement arm portions 31 a, 31 b, 33 a, and 33 b (41 a, 41 b, 43 a, and 43 b) continuing to the non-joint region 50 b, and the capacitor chips 20 can favorably be held by the arm portions. In addition, the metal terminal 30 (40) is easily elastically deformed, and an acoustic noise phenomenon can be prevented effectively.

Moreover, as shown in FIG. 3A, the end surfaces of the terminal electrodes 22 (24) of a plurality of chips 20 may be joined side by side with the terminal body 36 (46) in a plurality of joint regions 50 a, and the non-joint region 50 b is formed between the joint regions 50 a adjacent to each other. In this structure, a pair of metal terminals 30 and 40 can easily connect a plurality of chips 20, and an acoustic noise phenomenon can be prevented due to the existence of the non-joint region 50 b existing between the chips 20.

Moreover, in the present embodiment, the terminal body 36 (46) is provided with the second through holes 36 c going through the front and back surfaces of the terminal body 36 (46) in the non-joint region 50 b. The arm portions 31 b and 33 b (41 b and 43 b) extend from the opening peripheries of the second through holes 36 c. Since the second through holes 36 c are formed, the non-joint region 50 b can be formed easily, the arm portions 31 b and 33 b (41 b and 43 b) can be formed easily, and the chips 20 are held firmly.

Moreover, in the present embodiment, the protrusions 36 a protruding toward the end surface of the terminal electrode 22 (24) are formed on the inner surface of the terminal body 36 (46). This structure can easily control the joint region 50 a of the connection member 50 and also easily control a thickness of the joint region 50 a. In addition, this structure stabilizes the connection of the connection member even if the amount of the connection member is small.

In the present embodiment, vibrations do not travel from the chips 20 to the metal terminal 30 in the second through holes 36 c. Although vibrations are easily generated by electrostrictive phenomenon in the chips 20, particularly in a part where the internal electrodes 26 of the chip 20 are laminated via the dielectric layers, vibrations can be prevented from traveling in the second through holes 36 c in the present embodiment.

In the present embodiment, as shown in FIG. 2B, the non-joint region 50 b (the connection member 50 is not present between the terminal body 36 and the end surfaces of the terminal electrodes 22) is present in the non-opening region 36 c 1 of the terminal body 36 within a predetermined height L4 in the Z-axis direction corresponding to the second through holes 36 c shown in FIG. 3A. In the non-joint region 50 b, the terminal body 36 of the metal terminal 30 can freely elastically be deformed without being disturbed by the terminal electrodes 22, and stress is reduced. This favorably maintains an elastic property of the lower arm portions 31 b and 33 b as the holding pieces continuing to the non-opening regions 36 c 1, and the chips 20 can favorably be held by the lower arm portions 31 b and 33 b. In addition, the metal terminal 30 is easily elastically deformed, and an acoustic noise phenomenon can be prevented effectively.

Moreover, the lower arm portions 31 b and 33 b are formed in the second through holes 36 c near the mount portion in the present embodiment. In this structure, electrostrictive strain vibrations of the internal electrodes 26 can be prevented from traveling to the metal terminal 30 near the mount portion 38. The lower arm portions 31 b and 33 b are hard to be influenced by the electrostrictive strain vibrations and can securely hold the chips 20.

In the present embodiment, the lower arm portion 31 b (33 b) is formed by being bent from an opening edge of the second through hole 36 c. In this structure, the second through hole 36 c and the lower arm portion 31 b (33 b) can easily be formed and arranged closely, and it is possible to more effectively prevent a vibration transmission from the chips 20 to the metal terminal 30 and a vibration transmission from the metal terminal 30 to the mount board.

Second Embodiment

FIG. 1D is a schematic perspective view of a capacitor 10 a according to a variation of the capacitor 10 shown in FIG. 1A. In the metal terminal 30 of the capacitor 10 a shown in FIG. 1D, a base of the upper arm portion 31 a (a boundary between the arm portion 31 a and the terminal body 36) among the pair of arm portions 31 a and 31 b (the same applies to 33 a and 33 b/the same applies hereinafter) has a width Xa that is smaller than a width Xb of the lower arm portion 31 b, and the upper arm portion 31 a becomes wider from the base toward the tip. Moreover, in the present embodiment, a protrusion area Aa of the upper arm portion 31 a seen in the Z-axis direction is smaller than a protrusion area Ab of the lower arm portion 31 b seen in the Z-axis direction. Incidentally, the metal terminal 40 has similar structure to the metal terminal 30.

In this structure, the pair of arm portions 31 a and 31 b (33 a and 33 b) can stably hold the capacitor chip 20, and the capacitor chip 20 and the metal terminal 30 can securely and firmly be connected. Moreover, a contact area between the pair of arm portions 31 a and 31 b and the terminal electrode 22 of the capacitor chip 20 can be increased, and the capacitor chip 20 can be held more securely. Other structure of the present embodiment is similar to First Embodiment and demonstrates similar effects to First Embodiment.

Third Embodiment

FIG. 7 is a schematic perspective view of a capacitor 100 according to another embodiment of the present invention. FIG. 8 to FIG. 11 are respectively a front view, a left-side view, a top view, and a bottom view of the capacitor 100. As shown in FIG. 7, the capacitor 100 is similar to the capacitor 10 according to First Embodiment or the capacitor 10 a according to Second Embodiment except that the capacitor 100 has three capacitor chips 20 and a different number of first through holes 36 b or so contained in a first metal terminal 130 and a second metal terminal 140. In the description of the capacitor 100, similar parts to the capacitor 10 or 10 a are provided with similar references to the capacitor 10 and are not described.

As shown in FIG. 7, the capacitor chips 20 contained in the capacitor 100 are similar to the capacitor chips 20 contained in the capacitor 10 shown in FIG. 1. The three capacitor chips 20 contained in the capacitor 100 are arranged so that chip first sides 20 g are perpendicular to a mount surface as shown in FIG. 8, and that chip second sides 20 h are parallel to a mount surface as shown in FIG. 10. The three capacitor chips 20 contained in the capacitor 100 are arranged in parallel to a mount surface so that the first terminal electrodes 22 of the capacitor chips 20 adjacent to each other are mutually in contact with, and that the second terminal electrodes 24 of the capacitor chips 20 adjacent to each other are mutually in contact with.

The first metal terminal 130 contained in the capacitor 100 has a terminal body 136, three pairs of engagement arm portions 31 a, 31 b, 33 a, 33 b, 35 a, and 35 b, and a mount portion 138. The terminal body 136 faces the first terminal electrodes 22. The three pairs of engagement arm portions 31 a, 31 b, 33 a, 33 b, 35 a, and 35 b hold the capacitor chips 20. The mount portion 138 is bent perpendicularly from a terminal second side 136 hb of the terminal body 136 toward the capacitor chips 20. The terminal body 136 has a substantially rectangular flat shape and has a pair of terminal first sides 136 g approximately parallel to the chip first sides 20 g and a pair of terminal second sides 136 ha and 136 hb approximately parallel to the chip second sides 20 h.

As is the case with the first metal terminal 30 shown in FIG. 3A, the first metal terminal 130 is provided with the protrusions 36 a, the first through holes 36 b, the second through holes 36 c, and the slits 36 d as shown in FIG. 9. The first metal terminal 130 is, however, provided with three first through holes 36 b, three second through holes 36 c, and three slits 36 d, and one first through hole 36 b, one second through hole 36 c, and one slit 36 d correspond with one capacitor chip 20. The first metal terminal 130 is provided with 12 protrusions 36 a in total, and the four protrusions 36 a correspond with each of the capacitor chips 20.

In the first metal terminal 130, as shown in FIG. 10, the upper arm portion 31 a and the lower arm portion 31 b hold one of the capacitor chips 20, the upper arm portion 33 a and the lower arm portion 33 b hold another one of the capacitor chips 20, and the upper arm portion 35 a and the lower arm portion 35 b hold another one of the capacitor chips 20 that is different from the above two capacitor chips 20. The upper arm portions 31 a, 33 a, and 35 a are connected with the terminal second side 136 ha at the upper part of the terminal body 136 (upper side in the Z-axis direction), and the lower arm portions 31 b, 33 b, and 35 b are connected with periphery portions of the second through holes 36 c.

As shown in FIG. 8 and FIG. 11, the mount portion 138 of the first metal terminal 130 is connected with the terminal second side 136 hb at the lower part of the terminal body 136 (negative side in the Z-axis direction). The mount portion 138 extends from the terminal second side 136 hb toward the capacitor chips 20 (back in the Y-axis direction) and is bent approximately perpendicularly to the terminal body 136.

The second metal terminal 140 has a terminal body 146, a plurality of pairs of engagement arm portions 41 a, 43 a, and 45 a, and a mount portion 148. The terminal body 146 faces the second terminal electrodes 24. The engagement arm portions 41 a, 43 a, and 45 a sandwich and hold the capacitor chips 20 from both ends of the chip first sides 20 g in the Z-axis direction. The mount portion 148 extends from the terminal body 146 toward the capacitor chips 20 and is at least partially approximately perpendicular to the terminal body 146.

As is the case with the terminal body 136 of the first metal terminal 130, the terminal body 146 of the second metal terminal 140 has a pair of terminal first sides 146 g approximately parallel to the chip first sides 20 g and a terminal second side 146 ha approximately parallel to the chip second sides 20 h, and the terminal body 146 is provided with the protrusions 46 a, first through holes, second through holes, and slits. As shown in FIG. 7, the second metal terminal 140 is arranged symmetrically to the first metal terminal 130 and is different from the first metal terminal 130 in arrangement to the capacitor chips 20. The second metal terminal 140 is, however, different from the first metal terminal 130 only in arrangement and has a similar shape to the first metal terminal 130. Thus, the second metal terminal 140 is not described in detail.

The capacitor 100 according to the present embodiment has similar effects to those of the capacitor 10 according to First Embodiment. Incidentally, each number of upper arm portions 31 a to 35 a, lower arm portions 31 b to 35 b, first through holes 36 b, second through holes 36 c, and slits 36 d contained in the first metal terminal 130 of the capacitor 100 is the same as the number of capacitor chips 20 contained in the capacitor 100, but the number of engagement arm portions or so contained in the capacitor 100 is not limited thereto. For example, the first metal terminal 130 may be provided with twice as many first through holes 36 b as the capacitor chips 20, or may be provided with a single long slit 36 d continuing in the X-axis direction.

Fourth Embodiment

FIG. 3C is a left-side view illustrating a capacitor 300 according to another embodiment of the present invention. The capacitor 300 according to the present embodiment is similar to the capacitor 10 according to First Embodiment or the capacitor 10 a according to Second Embodiment except for the shape of slits 336 d formed on first and second metal terminals 330. As shown in FIG. 3C, the first and second metal terminals 330 are provided with a single slit 336 d formed below two second through holes 36 c and continuing in the X-axis direction. The slit 336 d has any shape and number as long as the slit 336 d is formed between lower edges (chip second sides 20 h) of the capacitor chips 20 facing the first end surfaces 20 a and the terminal second side 36 hb (i.e., terminal connection part 36 k).

Fifth Embodiment

FIG. 3D is a left-side view illustrating a capacitor 500 according to further another embodiment of the present invention. The capacitor 500 according to the present embodiment is similar to the capacitor 10 according to First Embodiment or the capacitor 10 a according to Second Embodiment except that notches (openings) 536 c are formed in first and second metal terminals 530 instead of the second through holes 36 c. As shown in FIG. 3D, the non-opening region 36 c 1 is formed in the middle of the first and second metal terminals 530 in the X-axis direction, and the notches 536 c are formed on both sides of the non-opening region 36 c 1. The notches 536 c are formed on the terminal body 36 so that a part of the terminal electrodes 22 (part of lower portion) corresponding to the internal electrode layers 26 at the lower part in the Z-axis direction is exposed to the outside.

Sixth Embodiment

FIG. 3E is a left-side view illustrating a capacitor 600 according to further another embodiment of the present invention. The capacitor 600 according to the present embodiment is similar to the capacitor 10 according to First Embodiment or the capacitor 10 a according to Second Embodiment except that only one capacitor chip 20 is connected to first and second metal terminals 630. In the present embodiment, similar effects to First Embodiment or Second Embodiment are demonstrated.

Other Embodiments

Incidentally, the present invention is not limited to the above-mentioned embodiments, and may variously be changed within the scope of the present invention.

In the example of FIG. 1B, for example, the upper arm portion 31 a (33 a) has a width Xa in the X-axis direction that is smaller than a width Xb of the lower arm portion 31 b (33 b) in the X-axis direction, but may have a width Xa in the X-axis direction that is larger than a width Xb of the lower arm portion 31 b (33 b) in the X-axis direction. In the example of FIG. 1C, the upper arm portion 31 a (33 a) has a protrusion length Ya in the Y-axis direction that is larger than a protrusion length Yb of the lower arm portion 31 b (33 b) in the Y-axis direction, but may have a protrusion length Ya in the Y-axis direction that is smaller than a protrusion length Yb of the lower arm portion 31 b (33 b) in the Y-axis direction.

For example, the metal terminals 30, 130, 40, 140, 330, 530, and 630 are provided with the protrusions 36 a, the first through hole 36 b, and the slit 36 d (or 336 d) as necessary, but the metal terminal of the present invention is not limited to these metal terminals, and the electronic device of the present invention includes a variation where one or more of these components are not formed.

In the present invention, the number of chips owned by the electronic device may be singular or any plural. For example, the metal terminals 130 and 140 of the capacitor 700 shown in FIG. 12 respectively have five capacitor chips 20 in the X-axis direction. Moreover, the metal terminals 130 and 140 of the capacitor 800 shown in FIG. 13 hold 10 capacitor chips 20 in the X-axis direction.

Moreover, for example, all of the arm portions 31 a, 31 b, 33 a, and 33 b shown in FIG. 2B are in contact with the first terminal electrode 22 of the capacitor chips 20 in First Embodiment, but not all of the arm portions 31 a, 31 b, 33 a, and 33 b need to be in contact with the first terminal electrode 22 after the joint region 50 a is formed. This is also the case with the other embodiments.

NUMERICAL REFERENCES

-   10, 10 a, 100, 200, 300, 500, 600, 700 . . . capacitor -   20 . . . capacitor chip -   20 a . . . first end surface -   20 b . . . second end surface -   20 c . . . first side surface -   20 d . . . second side surface -   20 e . . . third side surface -   20 f . . . fourth side surface -   20 g . . . chip first side -   20 h . . . chip second side -   20 j . . . chip third side -   22 . . . first terminal electrode -   24 . . . second terminal electrode -   26 . . . internal electrode layer -   28 . . . dielectric layer -   30, 130, 40, 140, 330, 430, 530 . . . metal terminal -   31 a, 33 a, 35 a, 41 a, 43 a, 45 a . . . upper arm portion (holding     piece) -   31 b, 33 b, 35 b, 41 b, 43 b . . . lower arm portion (holding piece) -   36, 136, 46, 146 . . . terminal body -   36 a, 46 a . . . protrusion -   36 b . . . first through hole -   36 c . . . second through hole -   36 c 1 . . . non-opening region -   36 d, 46 d . . . slit -   36 g . . . terminal first side -   36 ha, 36 hb . . . terminal second side -   38, 138, 48, 148 . . . mount portion -   50 . . . connection member -   50 a . . . joint region -   50 b . . . non-joint region -   50 c . . . initial application region -   50 d . . . non-joint gap 

What is claimed is:
 1. An electronic device comprising: a chip component including a terminal electrode formed on an element body; and a metal terminal connectable with the terminal electrode of the chip component, wherein the metal terminal includes: a terminal body facing an end surface of the terminal electrode of the chip component; and a pair of holding pieces formed on the terminal body and sandwiching the chip component, and a width of one of the pair of holding pieces is different from that of the other holding piece.
 2. An electronic device comprising: a chip component including a terminal electrode formed on an element body; and a metal terminal connectable with the terminal electrode of the chip component, wherein the metal terminal includes: a terminal body facing an end surface of the terminal electrode of the chip component; and a pair of holding pieces formed on the terminal body and sandwiching the chip component, and a protrusion length of one of the pair of holding pieces is different from that of the other holding piece.
 3. An electronic device comprising: a chip component including a terminal electrode formed on an element body; and a metal terminal connectable with the terminal electrode of the chip component, wherein the metal terminal includes: a terminal body facing an end surface of the terminal electrode of the chip component; and a pair of holding pieces formed on the terminal body and sandwiching the chip component, and a protrusion area of one of the pair of holding pieces is different from that of the other holding piece.
 4. The electronic device according to claim 1, wherein a width of one of the pair of holding pieces varies from a base toward a tip of the holding piece.
 5. The electronic device according to claim 2, wherein a width of one of the pair of holding pieces varies from a base toward a tip of the holding piece.
 6. The electronic device according to claim 3, wherein a width of one of the pair of holding pieces varies from a base toward a tip of the holding piece.
 7. The electronic device according to claim 1, wherein the other holding piece is made of a plate piece corresponding to a punched hole formed on the terminal body.
 8. The electronic device according to claim 2, wherein the other holding piece is made of a plate piece corresponding to a punched hole formed on the terminal body.
 9. The electronic device according to claim 3, wherein the other holding piece is made of a plate piece corresponding to a punched hole formed on the terminal body.
 10. The electronic device according to claim 1, wherein a slit is formed near the other holding piece on the terminal body.
 11. The electronic device according to claim 2, wherein a slit is formed near the other holding piece on the terminal body.
 12. The electronic device according to claim 3, wherein a slit is formed near the other holding piece on the terminal body.
 13. The electronic device according to claim 1, wherein the metal terminal further includes a mount portion configured to be mounted on a mount surface, the pair of holding pieces is formed on the terminal body so as to be positioned on both sides in a longitudinal direction of the end surface of the terminal electrode of the chip component, and one of the holding pieces is positioned farther from the mount portion than the other holding piece.
 14. The electronic device according to claim 2, wherein the metal terminal further includes a mount portion configured to be mounted on a mount surface, the pair of holding pieces is formed on the terminal body so as to be positioned on both sides in a longitudinal direction of the end surface of the terminal electrode of the chip component, and one of the holding pieces is positioned farther from the mount portion than the other holding piece.
 15. The electronic device according to claim 3, wherein the metal terminal further includes a mount portion configured to be mounted on a mount surface, the pair of holding pieces is formed on the terminal body so as to be positioned on both sides in a longitudinal direction of the end surface of the terminal electrode of the chip component, and one of the holding pieces is positioned farther from the mount portion than the other holding piece.
 16. The electronic device according to claim 1, wherein the terminal body is connectable to ends of a plurality of chip components horizontally arranged side by side, the pair of holding pieces is formed on the main body for each of the chip components, and one of the pair of holding pieces in each of the chip components is formed at one end of the terminal body.
 17. The electronic device according to claim 2, wherein the terminal body is connectable to ends of a plurality of chip components horizontally arranged side by side, the pair of holding pieces is formed on the main body for each of the chip components, and one of the pair of holding pieces in each of the chip components is formed at one end of the terminal body.
 18. The electronic device according to claim 3, wherein the terminal body is connectable to ends of a plurality of chip components horizontally arranged side by side, the pair of holding pieces is formed on the main body for each of the chip components, and one of the pair of holding pieces in each of the chip components is formed at one end of the terminal body.
 19. The electronic device according to claim 1, wherein a space region between the terminal body and the end surface of the terminal electrode includes: a joint region having a connection member connecting the terminal body and the end surface of the terminal electrode within a predetermined range; and a non-joint region failing to have the connection member between an edge of the joint region and the holding piece.
 20. The electronic device according to claim 2, wherein a space region between the terminal body and the end surface of the terminal electrode includes: a joint region having a connection member connecting the terminal body and the end surface of the terminal electrode within a predetermined range; and a non-joint region failing to have the connection member between an edge of the joint region and the holding piece.
 21. The electronic device according to claim 3, wherein a space region between the terminal body and the end surface of the terminal electrode includes: a joint region having a connection member connecting the terminal body and the end surface of the terminal electrode within a predetermined range; and a non-joint region failing to have the connection member between an edge of the joint region and the holding piece. 